I upgraded to openrc 10 days ago and didn't notice anything untoward, but
after a few days Firefox 3.6.17 started reporting that it couldn't find
Flash. (I only use Flash for the BBC I-Player service.) I tried Opera,
Chrome and Seamonkey, and they either said the same or just sat and looked
at me when asked to stream audio.

I'm amd64 too, but run ~amd64 for flash and Firefox. 10.2 was a real piece of crap, but 10.3 has just hit portage and it seems fine so far.

On a related note, who's using gnash (which is in portage), or lightspark (in portage but masked)? Are they drop in replacements for flash? As they're source I imagine they may be a better alternative for amd64 than the 32 bit adobe player.